Heretofore the prior art has suggested the use of a bistable ferromagnetic wire of generally uniform composition having a central relatively "soft" core portion and an outer relatively "hard" magnetized shell portion with relatively low and high coercivity, respectively, whereby the magnetized shell portion is operable for magnetizing the core portion in a first direction with such magnetization of the core portion being reversible by application of a separate magnetic field and the shell portion being further operable to remagnetize the core portion in the said first direction upon removal of the said separate magnetic field. This type of magnetic wire is herein referred to as a bistable magnetic wire or bistable magnetic means, or the like, and at least one embodiment thereof is disclosed and described in U.S. Pat. No. 3,820,090 dated June 25, 1974, the teachings of which are herein incorporated by reference. Further, a least one method for manufacturing such a bistable magnetic wire or device is disclosed and described in U.S. Pat. No. 3,892,118 dated July 1, 1975, the teachings of which are also herein incorporated by reference.
The prior art has also, heretofore, suggested that such a bistable magnetic device, in association with a separate magnetic field and an inductive coil, could be employed for producing electrical pulses. One such arrangement for producing electrical pulses is disclosed and described in U.S. Pat. No. 3,757,754 dated Sept. 11, 1973, wherein, as at FIGS. 2 and 3 thereof, it is proposed that a rotatable member 20 be provided with a plurality of bistable magnetic wires 10 arranged in angularly spaced relationship thereabout so that as the rotatable member is rotated the bistable magnetic wires sequentially pass next to a stationary sensing head comprised of a permanent magnet and an inductive field-like coil wound about the magnet. Various problems have been found to exist with respect to such an arrangement as: by way of example and not limitation, the inability to obtain a sufficiently strong inductive voltage into the coil as to be able to reliably subsequently employ the resulting pulse signal for any control function; and the practical difficulty if not impossibility of sufficiently accurately locating and positioning the plurality of bistable magnetic wires on the rotatable member as to be assured of the necessary resulting accuracy of angular spacing as between successive bistable magnetic wires as well as the required consistency of dimensional spacing between the respective bistable magnetic wires and the separate magnet and coil assembly as such bistable magnetic wires travel past the separate magnet and coil assembly.
In U.S. Pat. No. 3,780,313 dated Dec. 18, 1973, the prior art again discloses and describes a pulse generating apparatus employing a plurality of rotatable bistable magnetic wires as already hereinbefore described.
Accordingly, the invention as herein disclosed and described is primarily directed to the solution of the prior art and other attendant and related problems. Even though the invention is illustrated as embodied within structure comprising an engine ignition distributor assembly, the invention is, of course, not so limited as will become apparent.